Finding food can be especially tough in winter, when the snow is deep and the prey is hidden. So foxes have developed a special technique: they dive headfirst through three feet of snow to find their unseen prey. Amazingly, this works — but only when the fox is facing northeast or southwest.
Robert Krulwich at NPR looks at the curious case of the hunting red-fox and it's almost compass-like sense of direction, which was noticed when Czech scientist Jaroslav Cerveny observed the foxes hunting in the winter and started looking at just what makes a successful hunt. When they weren't facing their preferred direction, the foxes were seldom successful. In fact, the preference for jumping NE/SW was there even beyond the winter season.
Of course, the fox isn't the only animal to have some interesting compass-related habits, a recent study found that dogs prefer to align their bodies along a north-south axis when they poop. Exactly why that happens isn't quite clear yet, just like the exact meaning behind the foxes jumping-preferences aren't known either. Though there is a theory that the reason behind it is a "magnetic sense" that foxes use to hunt. Krulwich explains: